title: Changes in gastrointestinal hormones and leptin after Roux-en-Y gastric bypass surgery.
abstract: BACKGROUND
  Roux-en-Y gastric bypass (RYGB) imparts long-term weight loss, the mechanisms for which are not well understood. Changes in leptin and gastrointestinal (GI) hormones, including glucagon-like peptide 1 (GLP-1), peptide YY (PYY), and ghrelin, may contribute to the relative success of RYGB compared with conventional weight loss methods. This study evaluated changes in GI hormones and leptin post-RYGB. The study also evaluated whether GI hormones differed after a short-term dose of protein or fat.
  
  
  METHODS
  GLP-1, PYY, ghrelin, and leptin were assessed in 16 women before RYGB and up to 1 year after RYGB. Plasma was collected before and at several times after a short-term equicaloric dose of protein or fat.
  
  
  RESULTS
  GLP-1 area under the curve (AUC) increased at week 6 and 1 year in the fat beverage (FAT-BEV) group compared with baseline. PYY AUC remained elevated at 1 year in the FAT-BEV group. Ghrelin AUC decreased at week 2, week 6, and 1 year in the protein beverage (PRO-BEV) group compared with baseline. Ghrelin AUC was lower in the PRO-BEV group compared with the FAT-BEV group at week 6. Fasted leptin decreased at all visits in both groups and was lower in the FAT-BEV group compared with the PRO-BEV group at 1 year.
  
  
  CONCLUSIONS
  Changes from baseline were evident for all GI hormones and leptin; some differences were evident soon after surgery (ghrelin, leptin), whereas others were maintained long term (GLP-1, PYY, ghrelin, leptin). In response to a short-term stimulus, protein suppressed ghrelin and fat potently stimulated GLP-1 and PYY. Future work in this area is warranted.
authors.affiliation: Department of Food Science and Nutrition, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Beckman
authors.forename: Tiffany R
authors.initials: TR
authors.lastname: Beckman
authors.forename: Shalamar D
authors.initials: SD
authors.lastname: Sibley
authors.forename: William
authors.initials: W
authors.lastname: Thomas
authors.forename: Sayeed
authors.initials: S
authors.lastname: Ikramuddin
authors.forename: Todd A
authors.initials: TA
authors.lastname: Kellogg
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Ghatei
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Bloom
authors.forename: Carel W
authors.initials: CW
authors.lastname: le Roux
authors.forename: Carrie P
authors.initials: CP
authors.lastname: Earthman
mesh_terms: D000328:Adult; D019540:Area Under Curve; D004041:Dietary Fats / Q000494:pharmacology*; D004044:Dietary Proteins / Q000494:pharmacology*; D005260:Female; D015390:Gastric Bypass; D005768:Gastrointestinal Hormones / Q000097:blood*; D054439:Ghrelin / Q000097:blood; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D006801:Humans; D020738:Leptin / Q000097:blood*; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood* / Q000601:surgery; D019894:Peptide YY / Q000097:blood; D011184:Postoperative Period; D015431:Weight Loss / Q000502:physiology*
chemical_list: D004041:Dietary Fats; D004044:Dietary Proteins; D005768:Gastrointestinal Hormones; D054439:Ghrelin; D020738:Leptin; D019894:Peptide YY; D052216:Glucagon-Like Peptide 1